Extracellular vesicles (EVs) are small lipid vesicles released by either any prokaryotic or eukaryotic cell, or both, with a biological role in cell-to-cell communication. In this work, we characterize the proteomes and nanomechanical properties of EVs released by tissue-culture cell-derived trypomastigotes (mammalian infective stage; (TCT)) and epimastigotes (insect stage; (E)) of Trypanosoma cruzi, the etiologic agent of Chagas disease. EVs of each stage were isolated by differential centrifugation and analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS), dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), electron microscopy and atomic force microscopy (AFM). Measurements of zeta-potential were also included. Results show marked differences in the surface molecular cargos of EVs between both stages, with a noteworthy expansion of all groups of trans-sialidase proteins in trypomastigote’s EVs. In contrast, chromosomal locations of trans-sialidases of EVs of epimastigotes were dramatically reduced and restricted to subtelomeric regions, indicating a possible regulatable expression of these proteins between both stages of the parasite. Regarding mechanical properties, EVs of trypomastigotes showed higher adhesion compared to the EVs of epimastigotes. These findings demonstrate the remarkable surface remodeling throughout the life cycle of T. cruzi, which shapes the physicochemical composition of the extracellular vesicles and could have an impact in the ability of these vesicles to participate in cell communication in completely different niches of infection.

Extracellular vesicles (EVs) are small lipid vesicles released by both prokaryotic and eukaryotic cells, involved in intercellular communication, immunomodulation and pathogenesis. In this study, we performed a characterization of the EVs produced by trophozoites of a clinical isolate of the free-living amoeba Naegleria fowleri (N. fowleri). Size distribution, zeta potential, protein profile and protease activity were analyzed. Under our incubation conditions, EVs of different sizes were observed, with a predominant population ranging from 206 to 227 nm. SDS-PAGE revealed protein bands of 25 to 260 KDa. The presence of antigenic proteins was confirmed by Western blot, which evidenced strongest recognition by rat polyclonal antibodies raised against N. fowleri in the region close to 80 KDa and included peptidases, as revealed by zymography. Proteins in selected immunorecognized bands were further identified using nano-ESI-MS/MS. A preliminary proteomic profile of the EVs identified at least 184 proteins as part of the vesicles’ cargo. Protease activity assays, in combination with the use of inhibitors, revealed the predominance of serine proteases. The present characterization uncovers the complexity of EVs produced by N. fowleri, suggesting their potential relevance in the release of virulence factors involved in pathogenicity. Owing to their cargo’s diversity, further research on EVs could reveal new therapeutic targets or biomarkers for developing rapid and accurate diagnostic tools for lethal infections such as the one caused by this amoeba.

Continuous improvements in morphological and histochemical analyses of Apis mellifera could improve our understanding of the anatomy and physiology of these insects at both the cellular and tissue level. In this work, two different approaches have been performed to add new data on the abdomen of worker bees: (i) Micro-computed tomography (Micro-CT), which allows the identification of small-scale structures (micrometers) with adequate/optimal resolution and avoids sample damage and, (ii) histochemical multi-staining with Periodic Acid-Schiff-Alcian blue, Lactophenol-Saphranin O and pentachrome staining to precisely characterize the histological structures of the midgut and hindgut. Micro-CT allowed high-resolution imaging of anatomical structures of the honeybee abdomen with particular emphasis on the proventriculus and pyloric valves, as well as the connection of the sting apparatus with the terminal abdominal ganglia. Furthermore, the histochemical analyses have allowed for the first-time description of ventricular telocytes in honeybees, a cell type located underneath the midgut epithelium characterized by thin and long cytoplasmic projections called telopodes. Overall, the analysis of these images could help the detailed anatomical description of the cryptic structures of honeybees and also the characterization of changes due to abiotic or biotic stress conditions.

Background: Trypanosoma cruzi is a protozoan parasite responsible for American trypanosomiasis or Chagas disease (CD). This disease is characterized by the presence of cardiac or gastrointestinal symptoms in many patients during the chronic phase, with cardiac symptoms being the most common and severe, affecting approximately 30% of all patients. Although the origin of these pathologies remains unclear, several mechanisms have been proposed, involving factors related to T. cruzi and the host immune response. Extracellular vesicles (EVs) have been studied for their role in parasite-host cell communication, in modulating the host’s immune response and more recently as diagnostic tools. Methodology and main findings: In this study, we describe the role of EVs released by trypomastigotes and the immune complexes (ICs) they form with anti-T. cruzi IgGs (EVs-IgG) in the development of cardiac symptoms compatible with Chagas cardiomyopathy in mice. Autoantibodies detection, electrocardiographic, histopathological, and immunological analyses in mice’s hearts were performed. The studies carried out revealed that, while the inoculation of EVs and ICs (seven intravenous injections of 2 µg of EVs and ICs over 21 days) did not elicit the appearance of autoantibodies, it led to ECG alterations (heart rate and PR interval), changes in heart cavity areas and wall thickness, and reduced expression of crucial proteins for heart function (connexin 43, tubulin, and dynein), as well as VCAM-1 and altered the cytokine expression profile in the heart. Finally, both EVs-inoculated and ICs-inoculated mice showed an increased presence of B-type natriuretic peptide (BNP) in serum, suggesting that EVs or ICs may participate in the onset of cardiac damage. Conclusions: Our results confirm the ability of EVs shed by the infective forms of T. cruzi and the immune complexes they form with IgG to induce cardiac alterations in mice similar to those described in the literature, in T. cruzi-infected mice as well as in Chagas disease patients. This study highlights the role of EVs in the pathogenicity of Chagas disease and reinforces the importance of considering them as virulence factors in the development of Chagas disease.

Background: Chagas disease is the third most important neglected tropical disease. There is no vaccine available, and only two drugs are generally prescribed for the treatment, both of which with a wide range of side effects. Our study ofT.cruziPHBs revealed a pleiotropic function in different stages of the parasite, participating actively in the transformation of the non-infective replicative epimastigote form into metacyclic trypomastigotes and also in the multiplication of intracellular amastigotes.Methodology/principal findings: To obtain and confirm our results, we applied several tools and techniques such as electron microscopy, immuno-electron microscopy, bioinformatics analysis and molecular biology. We transfectedT.cruziclones with the PHB genes, in order to overexpress the proteins and performed a CRISPR/Cas9 disruption to obtain partially silenced PHB1 parasites or completely silenced PHB2 parasites. The function of these proteins was also studied in the biology of the parasite, specifically in the transformation rate from non-infective forms to the metacyclic infective forms, and in their capacity of intracellular multiplication.Conclusion/significance: This research expands our understanding of the functions of PHBs in the life cycle of the parasite. It also highlights the protective role of prohibitins against ROS and reveals that the absence of PHB2 has a lethal effect on the parasite, a fact that could support the consideration of this protein as a possible target for therapeutic action.

Trypanosoma cruzi, the causative agent of Chagas disease, can cross the placental barrier and be transmitted congenitally, yet the mechanisms underlying this process remain incompletely understood. Recent evidence suggests that T. cruzi-derived extracellular vesicles (TcEVs) may facilitate placental invasion by modulating host–pathogen interactions. In this study, we examined the effects of TcEVs on human placental explants (HPEs), focusing on their capacity to disrupt tissue architecture and modulate matrix metalloproteinases MMP-2 and MMP-9, enzymes critical for extracellular matrix remodeling. Term placental chorionic villi were cultured ex vivo and exposed to TcEVs, heat-inactivated TcEVs, infective trypomastigotes, or combinations thereof. TcEVs induced ultrastructural damage, including trophoblast detachment and basal lamina disorganization, which were exacerbated by co-incubation with parasites. Immunohistochemistry and Western blotting revealed significant upregulation of MMP-2 and MMP-9, while gelatin zymography confirmed increased enzymatic activity. Our findings demonstrate that TcEVs independently and synergistically with T. cruzi compromise placental integrity by enhancing MMP expression and activity, thereby priming the placental microenvironment for parasite invasion. Targeting TcEVs signaling or MMP activation may represent a novel strategy to prevent congenital transmission of T. cruzi.